1. Field of the Invention
The present technology relates to a system for supplying power to an electronic device or an electric device and, more particularly, to a power supply system suitable for an electronic device or an electric device of mobile devices such as a mobile phone, a notebook-sized personal computer, a digital camera, and an electronic toy.
2. Related Art and Other Considerations
FIG. 12 shows a conventional configuration example of a non-contact power supply system using magnetic coupling. A power transmitter 100 has a primary coil 101 for transmitting power and a positioning projection 102, and a power receiver 103 has a secondary coil 104 for receiving power and a positioning recess 105.
As shown in FIG. 12, the primary coil 101 and the secondary coil 104 face each other in one-to-one correspondence and power is transmitted by magnetic coupling. When the primary coil 101 and the secondary coil 104 are apart from each other, power transmission efficiency deteriorates. Consequently, the primary coil 101 and the secondary coil 104 are disposed as close as possible by providing a projection and a recess such as the positioning projection 102 and the positioning recess 105 or by providing a guide (not shown) for positioning the power transmitter 100 and the power receiver 103 so that power can be supplied in a state of high power transmission efficiency.
In another conventional configuration example, by housing a power receiver in a box, corresponding to a power transmitter, made of a magnetic material, power is supplied to the power receiver in a non-contact manner. Such a method is also disclosed in, for example, Japanese Patent Application Laid-Open No. H04-317527 (hereinafter, referred to as “patent document 1”). At the time of providing a secondary coil in a power receiver, to realize high power transmission efficiency, the secondary coil has to be disposed in a predetermined position in the power receiver with high precision. There is another conventional configuration to assure the precision, in which a coil bobbin for a secondary coil is formed integrally with the body of a power receiver or a chassis housed in the power receiver body. Such a method is disclosed in, for example, Japanese Patent Application Laid-Open No. H10-97931 (hereinafter, referred to as “patent document 2”).
However, the conventional configuration example shown in FIG. 12 has a problem such that since the positional relation between the power transmitter 100 and the power receiver 103 is strictly limited and a spatial constraint is strong, the usability for the user is not good.
In the conventional configuration example of the patent document 1, the power receiver can be charged as long as it is housed in any position in the box. Therefore, it can be said that the positional relation between the power transmitter and the power receiver is less limited than that in the conventional configuration example of FIG. 12. However, the box itself has to be made of a magnetic material and, if the box is not closed, power cannot be effectively supplied. Consequently, the technique has a problem that the usability for the user is not good.
In the conventional configuration example disclosed in the patent document 2, the coil bobbin for the secondary coil is formed integrally with the body of the power receiver or the chassis housed in the power receiver body. Consequently, the positional relation between the secondary coil and the body of the power receiver can be maintained at relatively high precision. However, at the time of charging the power receiver, like the conventional configuration example shown in FIG. 12, a problem occurs such that the positional relation between the power transmitter having therein the primary coil and the power receiver is strictly limited.